Vessel structures can be visualized very well in particular using computed tomography (CT) techniques after injection of a contrast agent. Modern multiple-layer CT systems allow the recording and display of vessel structures with relatively high three-dimensional resolution, as is very important in particular for visualization of coronary vessel structures.
On the basis of the recorded 3D image data record, the user, when presented with a suitable visualization, can determine the relationship between the vessel lumen and the plaque deposit on the vessel, in order from this to estimate the risk of the patient having an infarct. The subsequent steps for treatment of the patient are then defined as a function of the result of this evaluation.
In this case, the 3D image data record of the examination volume in which the vessel structure is located is generally evaluated by means of standard visualization techniques, such as MPR (multiplanar reformatting) or using axial slice images along the central axis of the vessels. In these methods, the viewer is presented with the recorded 3D image data in the desired projection or in the desired slice plane, possibly after segmentation of the vessel structure, on a monitor. The three-dimensional relationship between the plaque deposit and the vessel lumen and thus the degree of stenosis are in this case generally determined on the basis of a display in the form of an image of the entire examination volume.
U.S. Pat. No. 4,945,478 A describes an image processing system for identification and 3D display of atherosclerotic deposits from MRT data records. For this purpose, the vessels are extracted by way of segmentation from the image data record, and plaque deposits are identified in the image data. The plaque deposits are classified in the method from this document in order to make it possible to visualize the different classification in the subsequent display.
The 3D visualization is produced on the basis of a “quadtree” display, in which the entire volume of interest is subdivided into cuboids, with each cuboid being allocated a specific brightness or color, which represents the corresponding classification of the plaque. In this case one or more of the original pixels in each cuboid is or are combined so as to also reduce the number of data items to be processed overall.